Change-speed device



Mar. 3, 1925. 1,528,452

I G. J. RACKHAM CHANGE SPEED DEVICE 7 Filed Sept. 24. 1923 2 Sheets-Sheet l i vfi; 9

Mar. 3, 1925. 1,528,452

G. J. RACKHAM CHANGE SPEED DEVI CE Filed p 24 1923 2 Sheets-Sheet 2 Patented Mar. 3, 1925.

" UNITED STATE imam,

GEORGE :r. RACKHAM, or orncao, ILLINOIS. Assrenon TO YELLOW commun o- FFIcE."

FACTURING 00., OF CHICAGO, ILLINOIS, .A CORPORATION OF ILLINOIS.

' CHANGE-swan nnv'rcn.

Application filed September 24, 1223. Serial lio. 664,524.

To all whomz't may concern: 4 'Be 1t known that I, Gnonon .T'. RACKHAM,

a subject of the King of England, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Change-Speed Devices, of which the following is a specifica- In connection with the foregoing, it will be understood that in the ordinary change speed transmission the passage from higher 5 to lower. speed combinations presents difficulties, owing to the fact that the speed of the transmission shaft should be increased as the gear ratio is multiplied, assuming that the speed of the propeller or driven shaft does not materially decrease. 'According to the present invention, however, I provide what I term a free wheel connection within the transmission mechanism, which free wheel connection is so constituted as to allow the driven or propeller shaft to run ahead of the transmission shaft in case the speed of thepropeller shaft tends to excoed that ofthe transmission shaft. This will. make it possible to re-engage the transmission shaft in the-new gear combination:

of lower order without particular reference to the actual speed of the propeller shaft itself, since the latter at such times is al-;

lowed to run ahead ,of the transmission shaft, which condition will continue until the speeds of the two shafts become gradually equalized, .or until the driving force applied by the enginecauses a driving tendency from the transmission shaft to the propeller shaft.

In connection with the foregoing free wheel attachment, I have also made proat such times the free wheel connection will not interfere with the proper'transmission of power.

Other objects and uses of the invention Wlll appear from a detailed description of the same. which consists in the features of construction andcombinations of parts hereinafter described and claimed.

In the drawings:

Figure '1 shows a horizontal .section through a gear transmission embodying the features of the present invention;

' Fig. 2 shows a fragmentary section on line 2-2 of Fig.1 looking in the direction of the arrows; and

Fig. 3 shows a cross section on line of Fig. 1 looking I'OWS- In'the drawings, the engine connection is established to the end-5 of the driving shaft 6, whlch driving shaft is journalled in the front head 7 of the transmission casing by the use of ball bearings 8 and 9. The driven shaft 10. which ordinarily connects to the universaljoint at the front end of the propeller shaft," is journalled in the rear head 11 of the casing by ball bearings 12 and 13.

The shafts 6 and 10 are placed in alignment with each other.

Intermediate betweenthe shafts 6 and 10 is a transmission shaft 14.. Its front end 15 is of reduced. =size and is journalled in the rear end of the driving shaft 6.by means of roller bearings 16. The rear end 17 of the:

in the direction of the arp transmission-shaft 14 is also of reduced size I and is journalled in the driven shaft 10 by "means of a'roller bearing 18.

The lay shaft 19 is placed at one side of the transmission shaft and is journalled in the front and rear heads of the casing by ball bearings 20 and '21 respectively. A pinion 22 on the rear'end of the driving shaft .6 meshes constantly with a gear 23 on the lay shaft 19, so that the lay shaft rotates at a fixed speed ratio with respect to the driving shaft 6.

On the. lay shaft 19 are forward drive gears, 24 and 25 and a reversing gear 26. The reversing gear is nonstantlyinmesh with an idler pinion 27 located upon a short jack shaft 28 at one vside ot the lay shaft.

Splined upon the transmission shaft His vision for the establishment of a proper a gear'29 which when movedin one direcdriving connection for. reverse drive, .so that two will mesh directly with the low-speed ios ' 29 is another series of clutch blocks 38 in 31 which, when the gear 30 is moved for wardly a sufiicient distance, will engage the clutch element 32 on the rear face of the pinion 22 on the driving shaft 6. This will establish direct drive.

The front end of the driven shaft 10 carries an annular flange 33 having on its for-v ward face a series of notches 34. The rear end of the transmission shaft 14 carries .a

plate-35 having a series of spring pressed dogs or pawls 36 which will engage the notches 34 when the transmission shaft 14 tends to drive the driven shaft 10 forwardly Onthe other hand, this arrangement allows the driven shaft 10 to run ahead of the transmission shaft when such driving effort is no longer applied or when the driving effort comes from the propeller shaft.

On the flange 33 is a series of clutch blocks 37, and on the rear face of the gear position to engage the clutch blocks 37 durmg the interval. when the gear 29 is engaged with the reversing idler pinion 27 Consc-- quently, during the reversing operation the free wheel connection becomes ineffective anddoes not interfere with the proper reverse drive.

The gears 29 and 30 may be shifted back and forth in any convenient: manner, but'in the arrangement illustrated I have provided shlfting bars 39and '40 which extend longitudinally of thecasing. The bar 39 has a fork 41 which engages a suitable collar on the gear 29, and the bar 40 has a fork 42 which engages a suitable collar of the gear 30. l

The followingis a sequence of movements in themordinary operation of this device: The parts are shown in Fig. 1 as standmg in neutral position. The first or low speed forward drive is secured by shifting the gear 29 forwardly into mesh with'the lay shaft pinion 25; the second speed forward is secured by restoring the pinion 29 to the position shown in Fig 1 and then shifting the pinion 30 into mesh with the lay shaft pinion 24; the direct forward drlve is secured by retaining the pinion 29 in the position shown in Fi 1 and shifting the pinion 30 clear over todiring its clutch element 31 into engagement with the clutch element 32 The reversing position is secured by leaving the pinion 30 in the position shown in Fig 1' and then shifting the pinion 29 rearwardly into engagement with the idler pinion 27 which. is driven from the. lay shaft through the medium of the pinion 26. At the same time the clutch teeth 38 engage the clutch teeth 37, so that the propeller shaft 10 is driven in reverse notwithstanding the presence of the free wheel attachment- I wish to point out-that this arrangement allows the propeller shaft to run ahead of the shaft 14 when driving forward in those cases in whichthe tendency is for the speed of the propeller to exceed that of the shaft 14 I wish to'point out the fact that while I have herein shown and described the features of the present invention as being applied part -icularly to a gear transmission, still they may also be applied to equal advantage in the case of transmission using chain drives: and in a companion application for Letters-Patent of the United States, on improvements in change speed transmissions and the like, executed by me of even date'herewith, I have illustrated a combination of parts including a chain drive transmission having applied thereto a free wheel attachment of thegeneral nature of the present invention; v

IVhile I have. herein shown and described only a certain embodiment of the features of my present invention, still I do not limit myselfto the same except as I may do so in the-claim.

,--I claim:

In a change speed transmission, the combination of driving and driven shafts in alignment with each other, the adjacent ends of such shafts being separated, a transends and in alignment with both of said shafts, a lay shaft parallel to the transmission'shaft, apermanent driving connection between the driving and lay shafts, a series of forward drive gears on the lay shaft of different sizes, a reversing gear on the lay nent on the driving shaft to. directly drive,

the transmission shaft, adriving connection between the tIaDSHUSSIOH "Shaft filnt'l the driven shaft, adapted to-.transm1t rotation only in the forward direction, and.a elut'ch device on the first mentioned transmission shaft gear adapted to engage a clutch dev ce on the "driven shaft when said gear is. in

engagement with the idler pinion aforesaid, substantially as described GEORGEJ. RACKHAM.

mission shaft intermediate between said 

